Java tutorial
/* * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing; import javax.swing.plaf.*; import javax.accessibility.*; import java.beans.JavaBean; import java.beans.BeanProperty; import java.io.ObjectOutputStream; import java.io.IOException; /** * <code>JSeparator</code> provides a general purpose component for * implementing divider lines - most commonly used as a divider * between menu items that breaks them up into logical groupings. * Instead of using <code>JSeparator</code> directly, * you can use the <code>JMenu</code> or <code>JPopupMenu</code> * <code>addSeparator</code> method to create and add a separator. * <code>JSeparator</code>s may also be used elsewhere in a GUI * wherever a visual divider is useful. * * <p> * * For more information and examples see * <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>, * a section in <em>The Java Tutorial.</em> * <p> * <strong>Warning:</strong> Swing is not thread safe. For more * information see <a * href="package-summary.html#threading">Swing's Threading * Policy</a>. * <p> * <strong>Warning:</strong> * Serialized objects of this class will not be compatible with * future Swing releases. The current serialization support is * appropriate for short term storage or RMI between applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans™ * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. * * @author Georges Saab * @author Jeff Shapiro * @since 1.2 */ @JavaBean(defaultProperty = "UI", description = "A divider between menu items.") @SwingContainer(false) @SuppressWarnings("serial") public class JSeparator extends JComponent implements SwingConstants, Accessible { /** * @see #getUIClassID * @see #readObject */ private static final String uiClassID = "SeparatorUI"; private int orientation = HORIZONTAL; /** Creates a new horizontal separator. */ public JSeparator() { this(HORIZONTAL); } /** * Creates a new separator with the specified horizontal or * vertical orientation. * * @param orientation an integer specifying * <code>SwingConstants.HORIZONTAL</code> or * <code>SwingConstants.VERTICAL</code> * @exception IllegalArgumentException if <code>orientation</code> * is neither <code>SwingConstants.HORIZONTAL</code> nor * <code>SwingConstants.VERTICAL</code> */ public JSeparator(int orientation) { checkOrientation(orientation); this.orientation = orientation; setFocusable(false); updateUI(); } /** * Returns the L&F object that renders this component. * * @return the SeparatorUI object that renders this component */ public SeparatorUI getUI() { return (SeparatorUI) ui; } /** * Sets the L&F object that renders this component. * * @param ui the SeparatorUI L&F object * @see UIDefaults#getUI */ @BeanProperty(hidden = true, visualUpdate = true, description = "The UI object that implements the Component's LookAndFeel.") public void setUI(SeparatorUI ui) { super.setUI(ui); } /** * Resets the UI property to a value from the current look and feel. * * @see JComponent#updateUI */ public void updateUI() { setUI((SeparatorUI) UIManager.getUI(this)); } /** * Returns the name of the L&F class that renders this component. * * @return the string "SeparatorUI" * @see JComponent#getUIClassID * @see UIDefaults#getUI */ @BeanProperty(bound = false) public String getUIClassID() { return uiClassID; } /** * See <code>readObject</code> and <code>writeObject</code> in * <code>JComponent</code> for more * information about serialization in Swing. */ private void writeObject(ObjectOutputStream s) throws IOException { s.defaultWriteObject(); if (getUIClassID().equals(uiClassID)) { byte count = JComponent.getWriteObjCounter(this); JComponent.setWriteObjCounter(this, --count); if (count == 0 && ui != null) { ui.installUI(this); } } } /** * Returns the orientation of this separator. * * @return The value of the orientation property, one of the * following constants defined in <code>SwingConstants</code>: * <code>VERTICAL</code>, or * <code>HORIZONTAL</code>. * * @see SwingConstants * @see #setOrientation */ public int getOrientation() { return this.orientation; } /** * Sets the orientation of the separator. * The default value of this property is HORIZONTAL. * @param orientation either <code>SwingConstants.HORIZONTAL</code> * or <code>SwingConstants.VERTICAL</code> * @exception IllegalArgumentException if <code>orientation</code> * is neither <code>SwingConstants.HORIZONTAL</code> * nor <code>SwingConstants.VERTICAL</code> * * @see SwingConstants * @see #getOrientation */ @BeanProperty(preferred = true, visualUpdate = true, enumerationValues = { "SwingConstants.HORIZONTAL", "SwingConstants.VERTICAL" }, description = "The orientation of the separator.") public void setOrientation(int orientation) { if (this.orientation == orientation) { return; } int oldValue = this.orientation; checkOrientation(orientation); this.orientation = orientation; firePropertyChange("orientation", oldValue, orientation); revalidate(); repaint(); } private void checkOrientation(int orientation) { switch (orientation) { case VERTICAL: case HORIZONTAL: break; default: throw new IllegalArgumentException("orientation must be one of: VERTICAL, HORIZONTAL"); } } /** * Returns a string representation of this <code>JSeparator</code>. * This method * is intended to be used only for debugging purposes, and the * content and format of the returned string may vary between * implementations. The returned string may be empty but may not * be <code>null</code>. * * @return a string representation of this <code>JSeparator</code> */ protected String paramString() { String orientationString = (orientation == HORIZONTAL ? "HORIZONTAL" : "VERTICAL"); return super.paramString() + ",orientation=" + orientationString; } ///////////////// // Accessibility support //////////////// /** * Gets the AccessibleContext associated with this JSeparator. * For separators, the AccessibleContext takes the form of an * AccessibleJSeparator. * A new AccessibleJSeparator instance is created if necessary. * * @return an AccessibleJSeparator that serves as the * AccessibleContext of this JSeparator */ @BeanProperty(bound = false) public AccessibleContext getAccessibleContext() { if (accessibleContext == null) { accessibleContext = new AccessibleJSeparator(); } return accessibleContext; } /** * This class implements accessibility support for the * <code>JSeparator</code> class. It provides an implementation of the * Java Accessibility API appropriate to separator user-interface elements. * <p> * <strong>Warning:</strong> * Serialized objects of this class will not be compatible with * future Swing releases. The current serialization support is * appropriate for short term storage or RMI between applications running * the same version of Swing. As of 1.4, support for long term storage * of all JavaBeans™ * has been added to the <code>java.beans</code> package. * Please see {@link java.beans.XMLEncoder}. */ @SuppressWarnings("serial") protected class AccessibleJSeparator extends AccessibleJComponent { /** * Get the role of this object. * * @return an instance of AccessibleRole describing the role of the * object */ public AccessibleRole getAccessibleRole() { return AccessibleRole.SEPARATOR; } } }